On 16 April 2010 15:59, zaxis z_a...@163.com wrote:
instance (BinaryDefer a, BinaryDefer b) = BinaryDefer (a,b) where
put (a,b) = put2 a b
get = get2 (,)
size x = let ~(a,b) = x in size a + size b
putFixed (a,b) = putFixed2 a b
getFixed = getFixed2 (,)
in `size` function,
Ivan,
in `size` function, what does the `~` mean ?
A lazy pattern match: http://en.wikibooks.org/wiki/Haskell/Laziness
(there is a better name for it, but I can't remember).
Irrefutable pattern? ;-)
Cheers,
Stefan
___
Haskell-Cafe mailing list
On 16/04/10 07:09, Ivan Miljenovic wrote:
On 16 April 2010 15:59, zaxis z_a...@163.com wrote:
instance (BinaryDefer a, BinaryDefer b) = BinaryDefer (a,b) where
put (a,b) = put2 a b
get = get2 (,)
size x = let ~(a,b) = x in size a + size b
putFixed (a,b) = putFixed2 a b
Ashley Yakeley ash...@semantic.org writes:
There's an impedance mismatch between the IEEE notion of equality
(under which -0.0 == 0.0), and the Haskell notion of equality (where
we'd want x == y to imply f x == f y).
Do we also want to modify equality for lazy bytestrings, where equality
is
Yitzchak Gale g...@sefer.org wrote:
Since they weren't mentioned in this thread, I'll point out that there
are better sources of entropy than /dev/random, /dev/urandom, and the
Windows API.
For example, the two sites
https://random.org/integers
Dear haskell-cafe,
I implemented the Floyd Warshall algorithm for finding the shortest
path in a dense graph in Haskell, but noted the performance was
extremely poor compared to C. Even using mutable unboxed arrays it was
running about 30 times slower. I rewrote the program several times, to
Hello Mathieu,
Friday, April 16, 2010, 12:06:06 PM, you wrote:
actions and then running them using sequence_. But still this program
runs 3 times slower than it's C counterpart:
ghc low-level code optimization cannot be compared with best modern C
compilers that's result of 20 years of
Hi Bulat,
ghc low-level code optimization cannot be compared with best modern C
compilers that's result of 20 years of optimization. ghc generates
machine code in rather simple idiomatic way, so it should be compared
to non-optimizing C compiler
Sure. But I was curious if to see whether
Hello Mathieu,
Friday, April 16, 2010, 12:42:29 PM, you wrote:
Sure. But I was curious if to see whether there was some optimization
I had missed, seeing as other similarly low level programs, such as
the nsieve benchmark of the language shootout, or the word counting
program, manage to run
For what is is worth:
$ ghc -cpp -O2 -ddump-asm Main.hs Main.s
$ time ./a.out
Allocating ...
Allocating ... done
real0m39.487s
user0m39.258s
sys 0m0.150s
$ ~/Programming/Checkouts/ghc.llvm/inplace/bin/ghc-stage2 -cpp -fllvm
-O2 Main.hs
$ time ./a.out
Allocating ...
Allocating ...
On 16/04/2010, at 18:06, Mathieu Boespflug wrote:
shortestPath :: [(Int, Int, Int)] - UArray Int Int
shortestPath g = runSTUArray $ do
let mnew = newArray (0, SIZE * SIZE) 1
mread arr i j = unsafeRead arr (i * SIZE + j)
mwrite arr i j x = unsafeWrite arr (i * SIZE + j) x
Hi all,
I'm having a rather weird problem,
Ghc-pkg list shows a package installed but doing a ghc -make will give an
error saying that It can't find a module that's supposed to be in the
installed package.
And cabal install always reinstall all the dependencies on every change. It
As a Haskeller who is forced to switch to Ocaml by the job market
(or at least by the job interview market), I could really use a Ocaml for
Haskellers tutorial.
I was wondering if there are others who have been in this situation
recently and can share a few pointers, or better yet, write a blog
Am Freitag 16 April 2010 11:28:54 schrieb Phyx:
Hi all,
I'm having a rather weird problem,
Ghc-pkg list shows a package installed but doing a ghc -make will give
an error saying that It can't find a module that's supposed to be in the
installed package.
And cabal install always
Hi
Ocaml's a fine alternative to Haskell, you could be 'forced' to use
say PHP, now that wouldn't be quite so nice...
For instance, I have heard that Ocaml is only fast when one uses loops
instead of folds, but I wonder if this is an overstatement.
Maybe this notion is from the standard
(sorry for the duplication, forgot to reply to the mailing list too)
Well, I did, I've completely unregistered the package,
Did a check and recache, both completed with no problem.
In detail what's happening is, I'm building a tool that requires
Haskell-src-exts, So I upgraded to the 1.9.0
Stephen Tetley wrote:
I suspect the difference between the ML module system vs. typeclasses
will be as important as lazy vs. strict. As a style point, Ocaml
programmers don't seem too prone to combinator mania - so I think
golf is a bit less popular over there.
Both the lack of laziness
Am Freitag 16 April 2010 14:06:16 schrieb Phyx:
(sorry for the duplication, forgot to reply to the mailing list too)
Well, I did, I've completely unregistered the package,
Did a check and recache, both completed with no problem.
In detail what's happening is, I'm building a tool that
I'm using cabal install,
$ ghc --make -O2 WinDll
WinDll\Lib\NativeMapping.hs:51:18:
Could not find module `Language.Haskell.Exts':
Use -v to see a list of the files searched for.
Is the error message I get when I try to just compile it normally
While
$ ghc-pkg find-module
What does ghc-pkg check say? You probably have inconsistent deps; as
such rebuild all packages that are broken.
A package wrapped in braces in the ghc-pkg list output means the same thing.
Phyx loneti...@gmail.com writes:
(sorry for the duplication, forgot to reply to the mailing list too)
forced to switch to Ocaml
That like saying that you broke up with Miss America and started going
out with the runner-up. Sucks to be you :)
I experimented with Ocaml for a little while and among other things I
found that technology stack that comes with GHC (compared to Ocaml) is
quite a bit
Stefan Holdermans ste...@vectorfabrics.com writes:
Irrefutable pattern? ;-)
Ahhh, yes, that's it. I knew it started with `i', but that's about it...
--
Ivan Lazar Miljenovic
ivan.miljeno...@gmail.com
IvanMiljenovic.wordpress.com
___
Haskell-Cafe
Am Freitag 16 April 2010 15:06:55 schrieb Phyx:
I'm using cabal install,
$ ghc --make -O2 WinDll
WinDll\Lib\NativeMapping.hs:51:18:
Could not find module `Language.Haskell.Exts':
Use -v to see a list of the files searched for.
Is the error message I get when I try to just
For the first part
$ cat foo.hs
module Main (main) where
import Language.Haskell.Exts
main :: IO ()
main = print $ readExtensions BangPatterns
$ ghc --make foo.hs
foo.hs:3:8:
Could not find module `Language.Haskell.Exts':
Use -v to see a list of the files searched for.
So same
Am Freitag 16 April 2010 15:40:38 schrieb Phyx:
For the first part
$ cat foo.hs
module Main (main) where
import Language.Haskell.Exts
main :: IO ()
main = print $ readExtensions BangPatterns
$ ghc --make foo.hs
foo.hs:3:8:
Could not find module `Language.Haskell.Exts':
Use
Hi,
Strangely enough, I did the opposit some time ago. Ocaml is way simpler than
haskell, in fact. There is no referential transparency, no laziness (though it
can be simulated with fun ()-x, but the type of a lazy expression is not the
same as the reduced expressions), no parallelism (the GC
From: Mathieu Boespflug mb...@tweag.net
Dear haskell-cafe,
I implemented the Floyd Warshall algorithm for finding the shortest
path in a dense graph in Haskell, but noted the performance was
extremely poor compared to C. Even using mutable unboxed arrays it was
running about 30 times
Hi John,
your transformation on the original program amounts to replacing all
occurrences of a Haskell literal with a Haskell variable. You will
therefore end up with something that looks like this :
loop sIZE = return ()
loop j = ...
sIZE is now a pattern variable, that is, the pattern of the
Hello John,
Friday, April 16, 2010, 7:41:06 PM, you wrote:
sIZE = 1500
and all references from SIZE to sIZE, something ... changes. A lot.
this one too? :D
let loop2 SIZE = return ()
--
Best regards,
Bulatmailto:bulat.zigans...@gmail.com
Am Freitag 16 April 2010 17:41:06 schrieb John Lato:
From: Mathieu Boespflug mb...@tweag.net
Dear haskell-cafe,
I implemented the Floyd Warshall algorithm for finding the shortest
path in a dense graph in Haskell, but noted the performance was
extremely poor compared to C. Even using
On Fri, Apr 16, 2010 at 5:02 PM, Daniel Fischer
daniel.is.fisc...@web.de wrote:
Am Freitag 16 April 2010 17:41:06 schrieb John Lato:
From: Mathieu Boespflug mb...@tweag.net
Dear haskell-cafe,
I implemented the Floyd Warshall algorithm for finding the shortest
path in a dense graph in
Hello,
I ran into this error while trying to install statistics. Does this
indicate that I need to upgrade my GHC before I can install?
k...@catskill:~/projects/ cabal update
Downloading the latest package list from hackage.haskell.org
k...@catskill:~/projects/ cabal install statistics
Sorry, I forgot to add my ghc version is 6.10.1 on OSX
k...@catskill:~/projects/ ghc --version
The Glorious Glasgow Haskell Compilation System, version 6.10.1
On Fri, Apr 16, 2010 at 1:08 PM, Keith Sheppard keiths...@gmail.com wrote:
Hello,
I ran into this error while trying to install
Am Freitag 16 April 2010 19:11:13 schrieb Keith Sheppard:
Sorry, I forgot to add my ghc version is 6.10.1 on OSX
k...@catskill:~/projects/ ghc --version
The Glorious Glasgow Haskell Compilation System, version 6.10.1
On Fri, Apr 16, 2010 at 1:08 PM, Keith Sheppard keiths...@gmail.com
wrote:
Hi everyone,
It's been a long time since I last posted to this list since I'm
currently working on something that is not directly Haskell-related, but
it still relates to functional programming in general.
Anyway imagine my surprise when an innocent search for some keywords (I
can't remember
On Fri, Apr 16, 2010 at 2:40 PM, Phyx loneti...@gmail.com wrote:
So same error. This isn't just limited to HSE though, it can't find packages
like random,time etc either. Keeps reinstalling them on every cabal install.
Am Freitag 16 April 2010 20:50:25 schrieb Brian Hulley:
revealed a link to a US Patent (7120900) for the idea of implementing
the Unicode Bidirectional Algorithm (UAX #9
http://www.unicode.org/reports/tr9) in Haskell, making use, as far as I
can tell, of nothing more than the normal approach
Brian Hulley reports a search similar to :
haskell unicode bidirectional
revealed a link to a US Patent (7120900) for the idea of implementing the
Unicode Bidirectional Algorithm (UAX #9
http://www.unicode.org/reports/tr9) in Haskell, making use, as far as I
can tell, of nothing more
On Thu, Apr 15, 2010 at 1:33 AM, Daniel Fischer
daniel.is.fisc...@web.de wrote:
Can some core expert please look at these and explain the difference?
I'm interested in an explanation too.
+1
The behaviour is consistent. GHC 6.8.3, 6.10.4, 6.12.1 and
6.13-20100416 all agree on the space
.
+1
The behaviour is consistent. GHC 6.8.3, 6.10.4, 6.12.1 and
6.13-20100416 all agree on the space leak. Here is the minimal program
I have with the leak:
Myself and others posted simpler programs that had similar bad behavior,
including the space leak (depending on optimizations flags). I
Well, it's in the user list because it can't find them in the global list.
With the exception of Haskell-src-exts all the other packages are already
available in my global list. I'll try installing global and see
-Original Message-
From: thebenmach...@googlemail.com
Well, when I try compiling using -package I get
$ ghc -package haskell-src-exts foo.hs
command line: cannot satisfy -package haskell-src-exts:
haskell-src-exts-1.9.0-1e9f470ed15bddc8bf59f4d012a82687 is unusable due
to m
issing or recursive dependencies:
I've tried your suggestion, and with the --global flag it does work, but
only if I keep using the global flag, when I just install as user again same
thing happens. Maybe something's wrong with the user package conf.
Unfortunately installing as global requires admin rights and installs the
tools
Stupid question: are you trying to build this package/use ghci as the
same user that has haskell-src-exts installed as a user?
Phyx loneti...@gmail.com writes:
I've tried your suggestion, and with the --global flag it does work, but
only if I keep using the global flag, when I just install as
By the way, I happen to have a little problem when I try to add data
compression/decompression.
Since its impossible to add binary treatments (I call binary treatment a
function which type is: ByteString - ByteString, e.g. compression), I made
my own package binary-communicator. (can be found on
Yes I am, I'm running it all as the same user.
-Original Message-
From: Ivan Lazar Miljenovic [mailto:ivan.miljeno...@gmail.com]
Sent: Saturday, April 17, 2010 00:45
To: Phyx
Cc: 'Ben Millwood'; haskell-cafe@haskell.org; daniel.is.fisc...@web.de
Subject: Re: [Haskell-cafe] ghc package
Hi Brent,
I'm sorry to hear that the non-injectivity issue bit you. It's bitten me
also at times, leading me to choose associated data types (injective)
instead of associated synonyms (potentially non-injective). And sometimes,
the data types route is problematic, as the new types aren't
Hello,
One major thing I haven't seen explicitly mentioned yet in this thread
is tail recursion. You have to write tail recursively in OCaml (or any
strict language) or you will blow the stack. While tail recursion is
often wrong (in terms of efficiency) in Haskell, it is always right in
OCaml.
Hi Martijn, I can reproduce the problem and investigate. My guess is that
something is getting garbage collected that shouldn't be...
I'll let you know what I figure out.
thanks,
chris
On Apr 7, 2010, at 3:02 PM, Martijn van Steenbergen wrote:
Dear café (CC John and Chris),
I'm having
hello --
this is mostly a question for roman, or don, i guess. suppose i have
a list of similarly-sized vectors, and i want to add them up (possibly
with coefficients), to yield a result vector. something like
module Main where
import qualified Data.Vector.Generic as V
import qualified
I am a little surprised by the shortcomings of Haskell mentioned in the
thread.
I was under the impression that Haskell was closest to Nirvana on the
usefulness vs safety graph.
In the paper Why FP matters - Laziness is stated as one of the two key
features of FP that allows conceptual
I think that this should be fixed with the latest version of the driver
(0.6.2). I was incorrectly squirreling away pointers that I'd acquired using
with or withCString. This worked -- sometimes. :)
Please let me know if you see any other problems.
thanks,
chris
On Apr 7, 2010, at 3:02 PM,
On Fri, Apr 16, 2010 at 8:32 PM, Ben midfi...@gmail.com wrote:
hello --
this is mostly a question for roman, or don, i guess. suppose i have
a list of similarly-sized vectors, and i want to add them up (possibly
with coefficients), to yield a result vector. something like
module Main
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